The present disclosure relates generally to an electrochemical cell. More particularly, the present disclosure relates to a high temperature electrochemical cell including a conductive matrix.
Typical electrochemical cells/batteries include a negative electrode, a positive electrode, and electrolyte materials. High temperature molten salt rechargeable batteries (for example, sodium-metal halide batteries), including a molten metal negative electrode (usually referred to as an anode) and a beta-alumina solid electrolyte in the cells, are of considerable interest for energy storage applications. In addition to the anode, the cells include a positive electrode (usually referred to as a cathode) that supplies/receives electrons during the charge/discharge of the battery. The solid electrolyte is typically placed in a casing to separate an interior space of the cell into an anode and a cathode, and functions as the membrane or “separator” between the anode and the cathode.
Current developments of the sodium-metal chloride batteries are focused on the improvement of the performance and the cycle life. When these batteries are employed in mobile and utility applications, the batteries may be subjected to several charge and discharge cycles. During discharge of these batteries, heat is produced. Most of the heat is generated in the core i.e., the cathode of a cell, due to joule heating and chemical reactions. The cell is typically air-cooled through the external walls of its casing. The fully charged battery typically has an anode only about half full of molten metal (e.g., sodium), thereby leaving an empty space (e.g., an air gap) in the anode. The air gap as well as the molten metal typically does not conduct heat. Thus, the core i.e., the cathode of the cell remains at a higher temperature than the casing due to inefficiencies (ineffective) in transmitting heat from the cathode to the casing. For example, after a few charge/discharge cycles (such as 10 cycles), the temperature at the core of a sodium metal-halide cell is approximately 50 degrees higher than that of the outer casing. Moreover, as the battery discharges, the amount of molten metal in the anode is reduced, which increases the height of air gap. This air gap further limits the thermal cooling ability of the cell/battery, and also increases travel distance for the electrons during discharge (i.e., reduces the electrical conduction between the cathode and the casing).
There continues to be a growing need in the art for an improved solution to the long-standing problem of the performance and the cycle life of the batteries. It may be therefore desirable to develop a cell deign for providing effective thermal and electrical conduction between the core (i.e., cathode) and the casing of the cell.